A common method for sharing a single antenna in a communications system is to use a transmit/receive (T/R) switch to alternate between coupling a relatively high power transmitter to the antenna and coupling a receiver to the antenna. In such a system, the high-power signal output by the transmitter typically requires the use of a T/R switch that is specially designed to handle such high-power signals. Designing a T/R switch to handle such high-power signals creates many technical difficulties, including difficulty of design, limited availability of off-the-shelf switches, reduced switch lifetime, and increased thermal heating.
Additionally, T/R switches generally produce port-to-port signal leakage. The leakage from the port coupled to the transmitter to the port coupled to the receiver is particularly unwanted For example, due to the high power output of the transmitter, leakage signals from the transmission signal may exceed the levels of expected receive signals. These high-power leakage signals can cause damage to sensitive receiver components or require design of a less sensitive receiver.